DK145408B - CATALYST AND USE OF THIS FOR THE MANUFACTURING OF METHANIC GASES - Google Patents

Description

IP (12) PROCEDURE WRITING OR 145408 B

(19) DENMARK

DIRECTORATE OF THE PATENT AND TRADEMARKET SYSTEM

(21) Application No. 6l 46/73 Int.CI.3 B 01 J 23/74 (22) Filing date 14 Nov. 1973 C 07 C 4/06 (24) Running day 14 Nov. 1 973 (41) Aim. available] May 6, 1974 (44) Presented Nov. 15; 1982 (86) International Application No. '' (86) International Filing Day _ (85) Continuation Day _ (62) Master Application No _

(30) Priority 15 Nov. g72, 2255909, DE

(71) Applicant BASF AKTIENGESELLSCHAFT, 6700 Ludwigshafen, DE.

(72) Inventor Franz Josef Broecker, DE: Guenter Zlrker, DE: Bruno

Triebskorn, DE: Laszlo Marosi, DE: Matthias Schwarzmann, DE: et al. (74) Hofman-Bang & Bout ard engineering firm.

Catalyst and its use in the production of methane-containing gases.

The invention relates to a catalyst of the kind set forth in the preamble of claim 1 and to a use thereof. Thus, the catalyst of the invention is prepared from defined aqueous solution-formed compounds of the so-called catalyst precursor type by drying, calcining and reduction, or it is recovered by precipitation of the catalyst precursors on aqueous Q phase suspended carriers and the use of the catalyst. is for the production of methane-containing gases by decomposition of hydrocarbons.

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such as, for example, methane, propane and butane, for gases containing substantially carbon monoxide and hydrogen (so-called synthesis gases) in association with nickel catalysts in the presence of water vapor have long been known. It is generally carried out at temperatures between 600 and 900 ° C. This reaction is referred to as steam reforming.

However, hydrocarbons can also be decomposed into methane-rich gases at lower temperatures with nickel catalysts. However, the formation of methane-rich gases based on hydrocarbons such as ethane, propane, butane or naphtha, etc. at low temperatures is, unlike steam reforming, an exothermic process. Therefore, this reaction is carried out under adiabatic conditions in shaft furnaces, while the production of synthesis gases is carried out in tube furnaces by steam reforming. German Patent Specification No. 1,180,481 discloses that one can react liquid hydrocarbons in the range of 400 to 550 ° G with water vapor. for methane-rich gases in connection with nickel catalysts on carriers (with methane content above 50 ° C after drying), the so-called enriched gases, when observing different ratios of steam to hydrocarbon in the reaction.

For this process, it is generally proposed to use nickel catalysts on carriers of the conventional type. However, it has been found that the nickel catalysts known from the high temperature vapor cleavage are not suitable for low temperature hydrocarbon decomposition because they generally exhibit too little activity since their carriers were mostly calcined at high temperature to satisfy the requirements for steam reforming.

Also, the alkali-free catalyst which contains 15 9 ^ nickel on alumina (cf. column 4, lines 29-49), mentioned in the preferred embodiment as a preferred embodiment, is not well suited for the process because only loads which are not greater than 0.5 kg hydrocarbon per per liter of catalyst and hour, such catalyst is permissible when maturities of approximately 14 days are obtained. However, such a procedure is uneconomical when not allowing catalyst loads of approx.

1 - 1.5 kg hydrocarbon per per liter of catalyst and hour (see comparative experiments in Examples 5 and 6).

German Patent Specification No. 1,227,603, issued by the same applicant, states that the catalyst life is, by a method of the kind described in English Patent No. 820,257, equivalent to the German Patent Specification cited above. No. 1,180,481, is relatively short, especially in cases where higher boiling hydrocarbons in the henzine boiling range are to be cleaved.

In the disclosed specification No. 1,227,603, the applicant manufactures a nickel hardening catalyst which, in addition to nickel and alumina, contains 0.75 - 8.6 # oxides, hydroxides and carbonates of alkali or alkaline earth metals, including magnesium. In column 2, from line 44, and column 3, to line 16, it is stated that optimum results are obtained using alkalis, especially potassium, as an additive to the catalyst. In all examples, as a result, potassium compounds as an alkalizing agent are also used.

The compulsory alkalization of nickel catalysts prior to their use for the vapor decomposition of especially liquid hydrocarbons in the temperature range between 350 and 1,000 ° C, ie both for the actual steam reforming method and for the production of enriched gases, is also proposed in German Pat.

1,199,427 from ICI.

Knowing the specified part of the prior art, it was natural for the average person skilled in the art to use alkali-containing catalysts for the decomposition of hydrocarbons, since it was generally believed that the separation of carbon on the catalyst could be stopped only for a reasonable period of time with alkali-containing nickel catalysts during the reaction. in economically favorable conditions, including small values of the ratio [HgOj / tO].

According to one skilled in the art, therefore, because of the disclosures in German Patent Specification No. 1,227 # 603, there was a prejudice against using alkali-free nickel catalysts to generate enriched gases because, on the one hand, the promoter effect of alkalis, such as, for example, potassium, was proven. and, on the other hand, one would only expect a negative result from the use of aluminum oxide as a carrier (cf. Example 9 and the comparative experiments of Example 8 in the present application).

It has now surprisingly been found that alkali-free catalysts containing nickel and alumina can be prepared in such a way that they are superior in comparison to the known catalysts in their use in the production of methane-containing gases when in the preparation of these catalysts, predetermined catalyst precursors are assumed and transferred to the actual catalyst by precipitation, drying, calcination and reduction, while at the same time ensuring that the temperature gradient specified in claim 1 is within the stated territory.

The catalyst according to the invention is characterized by the characterizing part of claim 1.

Although it is known from the previously filed application, but on the application date of the present application, application no. 3177/73 has not yet published a catalyst of the kind specified in the preamble of claim 1, but in the preparation of this known catalyst no use has been made of the interval of the temperature gradient between the drying and calcining steps specified in the characterizing part of claim 1.

The invention further relates to the use of this catalyst for the production of methane-containing, in particular methane-rich, gases, by the decomposition of hydrocarbons having from 2 to 30 O atoms, corresponding to a boiling range between 30 and 300 ° 0, in the presence of water vapor.

The invention therefore also includes an application of the kind set forth in the preamble of claim 4, which use is peculiar to the characterizing part of claim 4.

This reaction is - as already stated in the introduction - exothermic and, therefore, in the event that the reaction partner is preheated to a sufficiently high temperature, it can be conducted adiabatically in a shaft furnace. In connection with the known catalysts, this method was generally carried out in such a way that the starting materials were preheated to more than 350 ° 0 and introduced into the catalyst mass in such a way that the temperature of this mass was kept at a value of range between 400 and approx. 550 ° C (cf. German Laid-Open No. 1,180,481 and German Laid-Open No. 1,227,603).

5 145408

Using the Catalyst According to the invention, it is possible to carry out the aforementioned process at lower temperatures under adiabatic conditions. This means that the hydrocarbons serving as starting materials must be heated to a lower temperature, with a preheat temperature of 250 ° 0 being sufficient. Therefore, for adiabatic execution of the reaction, cleavage can be carried out in a temperature range between 250 and 550 ° 0, but preferably the process is carried out in a temperature range between 500 and 450 ° C and in particular in a temperature range between 300 and 400 ° 0. indications refer to preheating temperature «! of the water vapor / hydrocarbon mixture. This is dependent on the raw material used and can be selected the lower the lower the boiling hydrocarbon mixture and the higher the paraffin content of this hydrocarbon mixture.

As is well known, the equilibrium of the reaction and thus the methane content is! it in the gas very strongly temperature and pressure dependent. It is the higher the lower the reaction temperature and the higher the pressure is chosen.

In this connection, it is an advantage that the catalyst according to the invention can be used in a pressure range between 10 and 100 atm. overpressure. Preferably, pressures are selected in the range of 25 to 85 atm. overpressure.

As raw materials, hydrocarbons with a higher molecular weight than methane are considered. Preferably, mixtures of hydrocarbons having an average 0 number of And - C 2 q are used, acidifying to a boiling range of approx. 30 to 300 ° C. Particularly suitable are hydrocarbon mixtures consisting predominantly of paraffinic hydrocarbons. The number of paraffinic hydrocarbons in the mixture should not be less than 70% by volume.

The raw material (naphtha) must be desulfurized to a sulfur content of less than 0.5 ppm because the known nickel catalysts, similar to the inventive catalyst, cannot withstand higher sulfur content over a long period of time. This poisoning effect is common to all nickel slit catalysts so that the raw material must, in principle, be desulfurized to a high 6 145A08 degree. This desulfurization is known and is usually carried out with sulfur-solid catalysts.

The catalyst of the invention can be treated with 1.0 - 2.5 kg of naphtha / liter of catalyst and hour. Preferably, for technical plants, loads of between 1.2 and 1.5 kg of naphtha / liter of catalyst per hour are used. In comparative experiments, a load of 5 kg of naphtha / liter of catalyst and hour (cf. Example 8) is used to achieve similar effects within a reasonable time. The aforementioned load does not matter for the technical decomposition of liquid hydrocarbons. However, the catalyst of the invention is capable of reliably decomposing gasoline fractions with a final boiling point of up to 500 ° C up to a load of 2 kg of naphtha / liter of catalyst and hour. For fuels with a lower final boiling point, loads greater than 2. You can apply loads of up to 3.5 kg of naphtha / liter of catalyst and hour for cleavage of propane or butane. These indications show that the load depends on the hydrocarbon used.

The vapor / naphtha weight ratio should be at least 0.8. In the vapor decomposition with the catalyst, ratios in the range of 1.0 to 2.0 kg of steam per day are used. kg of naphtha. The use of higher ratios is not critical, but is prohibited for economic reasons. The need for water vapor is by the gout of the nature of the raw material. By using very low boiling hydrocarbons, smaller values can be selected for this ratio, especially when cleaving predominantly paraffinic hydrocarbons.

Preferably, clay hydrates are used as carriers. Thereby, any nickel content can be obtained in connection with the finished catalyst. Generally, nickel content is between 15 and 77.5% by weight.

The preparation of the catalyst of the invention is described in more detail in a later section of this specification. Example 1 of the present description describes the use of the catalyst for the decomposition of hydrocarbons to produce methane-containing gases. Examples 3 and 4 relate to the addition of the enriched gases produced in a first process step in a further catalytic process step. Example 2 describes how a refinery gas containing carbon oxides can be converted into a methane-rich gas in connection with the catalyst of the invention.

In Example 8, a comparison was made between the catalyst of the invention, A and a known catalyst according to German Patent Specification No. 1,180,481 (H 2 and H 2) as to their ratio in the production of methane-containing gases. These experiments strikingly show that the alkali-free catalyst of the invention, relative to the known catalysts, is very superior in activity, especially at such high loads as are currently used in the art.

Example 8 further shows that the catalyst of the invention (A) is also superior in comparison to the alkaline contacts of the prior art (cf. K) according to German Patent Specification No. 1,227,603 in all respects. In particular, one can emphasize the higher load capacity and the associated longer run time of the catalyst according to the invention in comparison with the alkali nickel catalysts used in the art. By using the catalysts to produce methane-rich gases, this increased activity of the catalyst has the advantage that the process can be carried out at lower temperatures, so that methane content in the range of between 65 and 75% by volume can be obtained already in a process step, a further catalytic process step and a subsequent drying and CO 2 wash can be converted into gases which can serve as exchange gases for natural gas and which exhibit the specifications required for these gases (sum Hg + CO maximum 0.1% by volume, calculated on the gas after the Oog wash).

In the preparation of methane, after the first catalytic process, flue gas can be cooled to temperatures below the reactor outlet temperature to condense the excess water. For this purpose, temperatures below 100 ° 0, e.g. temperatures in the range of 20 to 80 ° C (dry methanation).

8 145408

However, it is also possible that the water is only partially removed from the flue gases after the first catalytic process step and that the still aqueous fission gases are directly converted to methane-rich gases in a further catalytic step ("wet methanation", cf. Example 3 and 4).

Gases containing carbon oxides are used as starting materials for the reaction of the second catalytic step of the process. Particularly suitable are the enriched gases resulting from the naphtha cleavage at low temperatures, which can generally contain 50 - 75 $ methane, 19 - 25 $> carbon dioxide, up to 16 # hydrogen and up to 5 # carbon monoxide. It has been found that these dry gases can be introduced into the mass of the nickel catalyst without coking the catalyst at preheating temperatures in the range of 200 to 300 ° 0. This was surprising because in published German application No. 1,645,840 it was claimed that the post-methanization of enriched gases is feasible only in the presence of water because the nickel catalysts used for methanization tend to coking in the absence of water.

In the second catalytic treatment stage, loads can be selected in the range of between 2,000 and 10,000 NI of gas per hectare. liter of catalyst and hour. At higher carbon monoxide content of the flue gases, lower loads are selected, and conversely, at lower carbon monoxide content of the feedstock, slightly higher loads can be set. Loads between 3,000 and 7,000 NI of gas per unit are preferred. liter of catalyst and hour.

The following examples will illustrate the catalysts of the invention in comparison with the known catalysts as well as the technical advantages shown by the catalysts of the invention over the known catalysts.

The diagram below shows which catalysts are within the scope of the invention and which are outside the scope of the invention.

145408 9

catalysts

In accordance with the invention, catalysts outside the invention give A G 1 - 11, G 1 - 21, G 1 - 40 B%, H2, H3

C I

D K

E F

The preparation of the above-mentioned catalysts which are within the invention is described in the immediately following sections (Experiments 1-3), while the preparation of the known catalysts is described in connection with the application experiments described in later sections.

EXPERIMENT 1

To precipitate the compound NigAlg (OH) + · 003 * 4Η20, which serves as a catalyst precursor, 2 molar solutions were first prepared:

Solution 1: 13,960 kg = 48 moles of Ni (NO3) 2 * 6H2O and 6.002 kg = 16 moles Al (NO3) 3 * 9H2O were dissolved in such a volume of water that a solution was obtained whose total volume was 32 liters.

Solution 2: 7.635 kg = 72 moles of sodium carbonate was also dissolved in water and made up to 36 liters.

10 liters of water were introduced into a stirrer. The pH measurement during the precipitation was performed with an electrode which dipped into the water publisher. Both solutions and the water publisher were separately heated to 80 ° 0. By adding a suitable amount of solution 2, a pH value of 8.0 was adjusted in the water publisher.

145408 ίο

To precipitate the above compound, solution 1 and solution 2 were separately lifted into the water publisher and maintained under good stirring by adjusting the feed rate a pH of 7.5 - 8.0. After complete addition of solution 1, the addition of solution 2 was stopped and the precipitate was still stirred for 15 minutes at 80 ° 0. The resulting precipitate was filtered off and washed alkali-free. The washed product, which, by X-rayography, proved to be a flawless precipitate of NigAl2 (0H) .g0 CO3 * 4H2O, then dried for 24 hours at 110 ° C, calcined for 20 hours at 450 ° 0 and then compressed with 2 $ graphite additive for 5 x 5 mm pills. For analytical purposes, the following values were obtained for the components (all indications Γ% by weight and calculated in relation to the oxidic contact): Nickel 56.8, aluminum 9.5 and sodium 0.009.

EXPERIMENT 2

Catalyst B:

Catalyst B contains as clay a clay hydrate. This clay hydrate was prepared by parallel precipitation of sodium aluminate solution and nitric acid in a pH range of 7.5 - 8.0. The precipitate was filtered, washed alkali-free and finally dried at 200 ° 0.

5.720 kg of this spring was suspended in a stirrer in 10 liters of water and heated to 80 ° C. The compound NigAl 2 (0H) 1600 ^ · 4Η20 was now precipitated on this suspended spring. For this purpose, two solutions were prepared and heated separately to 80 ° C.

Solution 1: 13,960 kg = 48 moles Ni (NO3) 2 · 6H20 and 6.002 kg = 16 moles Α1 (303) 3 · 9es20 dissolved in water and added up to 32 liters of solution.

Solution 2; 7.635 kg of technical soda was dissolved in water and up to 36 liters of solution was added.

145408 11

Then, as described in Example 1, at pH = 7.5 - 8.0 the compound NigAl2 (OH) precipitates on the clay hydrate (carrier). The precipitate from the precipitate was further stirred for 15 minutes, and then the precipitate was filtered off, washed alkali-free, dried at 110 ° C, calcined for 20 hours at 450 ° C and finally compressed into pellets with the dimension of 5 to 5 m after 2 $ graphite addition . The analysis showed the following values for the composition of the oxidic contact (all percentages by weight): 39.3 nickel, 24.1 aluminum, 0.01 sodium, were prepared as above, with the difference that the compound NigAl2 (OH was precipitated at 4,080 kg of the slurry carrier and that the dry precipitation was calcined at 350 ° C. The resulting catalyst (oxidic) had the following composition (all percentages by weight): 32.5 27.1 aluminum and 0.009 sodium.

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Kator__D: was prepared as catalyst C, but only with the difference that the amount of clay hydrate present was changed. A carrier contact was obtained with the following composition (all percentages by weight): 16.7 nickel, 38.3 aluminum and 0.007 sodium.

Catalyst E: was prepared as Catalysts C and D, except that the compound Ν16Α12 (ΟΗ) 00 00 00 · 4Η20 was precipitated on 6,830 kg of slurry clay hydrate. The resulting catalyst has led to the oxidic state of the following composition (all percentages by weight): 23.9 nickel, 31.4 aluminum and 0.01 sodium.

TRY 3 or_F:

By parallel precipitation of an aluminum sulfate solution with ammonia at pH = 7.5, a clay hydrate support was prepared. The precipitate was filtered, washed so long that the sulfate content was less than 0.5% by weight, and dried at 200 ° 0.

0.134 of this carrier material was suspended in a stirrer in 10 liters of water. As described in Experiment 2, the compound NigAl 2 (OH) 2 g CO 2 .4H 2 O precipitated on the clay hydrate. The precipitate was filtered, washed, dried at 110 ° C, calcined at 350 ° C for 20 hours and finally compressed into pellets of dimensions 5x5 mm.

A catalyst was obtained having the following composition (all percentages by weight): 52.4 nickel, 12.2 aluminum, 0.006 sodium.

EXAMPLE 1 200 ml of Catalyst A was reduced in a reaction tube having an internal diameter of 24 mm and which could be heated from the outside with an aluminum block, at a pressure of 16 atm. definitely with hydrogen at 450 ° C.

A desulfurized naphtha (density: 0.727 g / cm 2, boiling range 80 - 155 ° C) was evaporated while adding 2 kg of water per minute. kg of naphtha and was conducted under a pressure of 30 atm. absolutely with an inlet temperature of 380 ° C through the catalyst. The catalyst load was 5 kg of naphtha. liter of catalyst and hour. The temperature of the surrounding aluminum block was kept at 450 ° C. By cooling the decomposed decomposing gas with a temperature of 462 ° 0, the catalyst layer was obtained. 1.31 kg of water and 1770 NI of dry gas consisting of 65.9% by volume of methane, 23.1% by volume of carbon dioxide, 10.6% by volume of hydrogen and 0.4% by volume of carbon monoxide.

S2 £ 2LZ £ ator_B:

Catalyst B was obtained with the same feedstock and under the conditions set out above, a flue gas exiting the catalyst mass at a temperature of 470 ° C was obtained by cooling the flue gas. 1.31 kg of water and 1680 NI of a dry gas consisting of (all percentages by volume) 64.8 methane, 23.0 carbon dioxide, 11.7 hydrogen and 0.5 carbon monoxide.

145408 13

Catalyst g:

Catalyst F was used under the same conditions as A and B for the cleavage of naphtha. By cooling the decomposed flue gas leaving the catalyst layer at a temperature of 468 ° O, 1.30 kg of water and 1750 NI of a dry gas consisting of 65.0 methane, 23.1 carbon dioxide, 11.4 hydrogen and 0.5 carbon monoxide (all percentages by volume).

EXAMPLE 2

Catalyst C: 200 ml of Catalyst C was reduced in a reactor tube having an internal diameter of 24 mm and which could be heated from the outside with a r "aluminum block, under a pressure of 16 atm absolute, with hydrogen at 400 ° C.

One. dry gas consisting of (all percentages by volume) 60.5 methane, 25.9 hydrogen, 12.5 carbon dioxide, and 1.1 carbon monoxide was taken from a pressure vessel, heated and mixed with water vapor in the ratio 1.07 mol moles of dry gas.

Legs thus produced, wet gas which, in terms of the composition, correspond to a split gas produced by catalytic vapor decomposition of a refinery gas, were passed through the catalyst with a catalyst load of 6020 NI wet gas per minute. liter kata «t lysator and hour, at a pressure of 17 atm. absolute and at an Inlet temperature of 270 ° 0. The temperature of the surrounding aluminum block was kept at 270 ° C. By cooling it with a temperature of 295 ° 0 from the catalyst layer, wet gas exiting was obtained. 0.56 liters of water and 450 NI of dry gas consisting of 85.5 methane, 4 * 3 hydrogen, 10.2 carbon dioxide and less than 0.05 carbon monoxide (all percentages),

Catalyst Ώ was used under the same conditions to post-methanize a refinery flue gas containing ear-oxides as described in connection with Catalyst C, 145408 14

By cooling the wet gas extracting from the catalyst layer with a temperature of 300 ° C, a. 0.56 liters of water and 450 NI of a dry gas consisting of 84.9 methane, 5.0 hydrogen, 10.1 carbon dioxide and less than 0.05 carbon monoxide (all percentages by volume).

EXAMPLE 3 450 ml of Catalyst A remained. 450 ° C reduced by hydrogen in a reaction tube having an internal diameter of 24 mm and which could be heated from the outside with an aluminum block, at a pressure of 16 atm. abs.

A sulfurized naphtha (density 0.727 g / cm; boiling range 80 - 155 ° C) was added with 2 kg of water per ml. kg of naphtha evaporated and passed through the catalyst with an inlet temperature of 400 ° 0 and under a pressure of 30 atm. absolutely. The catalyst load was 0.9 kg of naphtha. liter of catalyst and hour. The temperature of the surrounding aluminum block was kept at 450 ° 0. By cooling the leaving gas leaving the catalyst layer at 455 ° C, the decomposition gas was obtained. 0.54 kg of water and 700 NI of a dry gas consisting of 67.1 methane, 22.9 carbon dioxide, 9.6 hydrogen and 0.4 carbon monoxide (all percentages by volume).

After 24 hours, a second reaction tube was inserted after the first reaction tube, which could also be heated from the outside with an aluminum block and had an internal diameter of 32 mm. This second reaction tube contained 250 ml of catalyst E which had already been reduced with hydrogen at 350 ° C under a pressure of 16 atm. absolutely. The amount of water condensed after the first reaction tube was again dosed before the second reaction tube, evaporated and mixed with the dry gas from the first reaction tube. The wet gas thus obtained (which, in terms of its composition, corresponds to the wet gas emerging from the catalyst layer in the first reaction tube) was conducted under a pressure of 30 atm. absolutely through the catalyst present in the second reaction tube. an inlet temperature of, .270 ° C. Sei ^ erø ^ ur ^ f; of the surrounding aluminum block was kept at 270 ° C. Upon cooling it at a temperature of 305 ° 0 from the catalyst layer, the extraction wire. h. the gas obtained per hour. © ©,, 56 leg ...-. vsgauåj., o ^ g [650.ΙΪ3. · It consisted of 75.6 methane, 22.8 carbon dioxide, 1.6 hydrogen and jt! less than 0.05 carbon monoxide (all angles of 1

After 1040 hours, no Vi could be found.

changing the composition of the gases produced in the first and second reaction tubes. Continueing the naphtha gap in the first reaction tube, catalyst was now replaced; * E in the second reaction tube with catalyst 2): 250 ml of catalyst: Sator D was reduced and used for 1090 hours under the same conditions as before catalyst E. By cooling it at a temperature of 302 ° C from the catalyst layer outgoing gas 0.56 kg of water and 660 NI of a dry gas which consumed 74.0 methane, 22.8 carbon dioxide, 3.2 hydrogen and less than 0.05 carbon monoxide (all percentages by volume). ~ of the gases formed in the first and second reaction tubes did not later change, the attempt was discontinued after 1220 hours. 5 i. , '', '·. "'?> <H" ':' .i

. EXAMPLE 4. "we V

As described in Example 3, 200 ml of Catalyst A was reduced and, under conditions that, with the exception of shelter, put the orb loading, which now amounted to 2.0 kg of naphtha per liter. liter of catalyst and hour - were the same as given in Example 3, nvsdd ^^ for vapor decomposition of naphtha. Upon cooling, the one with a temp.;. "475 ° R temperature from the catalyst layer was withdrawn. hourly 0.53 kg of water and 710 Nl., of. $ as, .dar, | f .... r3, 66.2 methane, 22.4 carbon dioxide, 10.9 hydrogen and 0.5 carban «on oxide (all percentages by volume;). r,, nm / 'Ο / · .. - ir-icon r-V' t-:; \ i yt $ .S * 7 * '.ir- - ·. ·, - · ·; ί -;! :; '> · Ε ·; :,; : ... ': ^. . ::: .i ;; i.:·:; v; ir i.1 '' 145403 16

After a 24 hour run, after the first reaction tube, a second reaction tube containing 200 ml of catalyst C. was introduced. gas extracted from the catalyst layer was obtained per 0.56 kg of water and 650 NI of a dry gas consisting of 75.4 methane, 22.9 carbon dioxide, 3.2 hydrogen and less than 0.05 carbon monoxide (all percentages by volume).

The test was discontinued after 520 hours, as after this time no change in the composition of the gases produced in the first and second reaction tubes was detected.

EXAMPLE 5

The comparative experiments were carried out under the conditions set out in Examples 1 and 2 of German Patent Specification No. 1,180,481, namely:

Catalyst temperature ...................... 500 ° C

Pore heating temperature of the mixture ...... 450 ° C

Pressure ....................................... 25 atm.

Substance used ............................... light petrol

Water vapor-gasoline ratio .................... 2 kg / kg

Load ................................. 0.5 kg gasoline / 1 cat. * H

Len used light petrol had a density of 0.693 g / cm 2 (at 20 ° C) and a boiling range from 63 to 102 ° C. Len contained 88% by volume paraffins, 10% by volume 6-ring naphthenes and 2% by volume aromatics. If nothing was stated in connection with the catalyst load in the examples, the low catalyst load indicated above was selected.

Three commercial BASP nickel catalysts suitable for high temperature vapor decomposition were compared

145403 17 (G 1 - 11, G 1 - 21 and G 1 - 40) and the special catalyst (H · ^) cited in the cited disclosure containing 15% nickel. The following table lists the nickel content, the carrier of the specified catalysts * and their trade names:. in

nickel

Catalyst type weight - # Carrier_ G 1 - 11 6 Magnesite G 1 - 21 16 Kaolin + magnesium oxide + clay cement G 1 - 40 20 Magnesium oxide + clay H1; prepared in accordance with Bei1 ': hold to MS j in 1,180,481, column 4, line 29 et seq.

The experiments were conducted in a reaction tube containing in each case 270 cm 2 of the catalysts indicated.

- * 1 '£ * V r; - 10 145408 1 o

The results of the experiments are presented in the following table:

Catalyst Catalyst Catalyst H1 $ MS

G 1 - 11 G 1 - 21 G 1 - 40 1,180,481

Duration, weight percent weight percent weight percent weight percent days gasoline converted gasoline converted gasoline converted gasoline

Beginning 100.0 100.0 96.7 100 1 93.4 97.9 94.0 100 2 82.0 82.6 93.1 100 3 43.7 53.0 91.6 100 4 - 36.9 76 , 1 100 5 - 23.3 75.0 100 6 30.2 15.9 - 100 7 18.8 32.7 54.5 100 8 10.7 - - 100 9 - 29.9 61.0 100 10 48 , 2 100 12 18.5 100 H - - 0 100

The experiments show that the process cannot be carried out with the commercial nickel-splitting catalysts because all three catalysts become inactivated in a very short time. The test with catalyst G 1 - 11 was discontinued after 8 days at a turnover of only 11% by weight, the test with catalyst G 1 - 21 was discontinued after 9 days at a turnover of 30% by weight. Since the test with catalyst G 1 - 40 after 9 days, still showed a turnover of 61% by weight of the gasoline, this experiment was extended to a total of 14 days.

After this time, the catalyst was completely inactivated and no gasoline was reacted at all. This also shows that there is no stabilization of the catalyst activity, but that the deterioration of activity progresses until the complete inactivation of a catalyst in a very short time.

145408 19

These experiments show that nickel catalysts are quite simple; J is not suitable for the method set forth in the cited script]. Only the special, special nickel catalyst produced in accordance with German Patent No. 1,180,481 with a pure clay support proved to be very limited in scope. The experiment with this catalyst was also extended to H days. In this period, the catalyst j reacted completely with petrol, but with a technical load of 1 kg of naphtha -J per liter of catalyst and hour, however, no complete naphtha decomposition is possible with this catalyst (cf. example 6).

In connection with the experimental method, it should be noted that high * -carbon hydrocarbons could be detected by gas chromatographic> up to 1 ppm.

EXAMPLE 6,

Test conditions:

Catalyst temperature (Al block temperature max.) ..................... 470 ° C i

Preheating temperature of the mixture .......... 420 ° C

Pressure .......................................... 30 atm.

Applied Substance .................................. Naphtha

Water vapor / gasoline ratio ...................... 2 kg / kg

Load .................................... 1 kg of naphtha / 1 cat. * H

The naphtha used had a density of 0.728 g / cm ** at 20 ° C and a boiling range between 80 and 150 ° 0. It contained 62% by volume of paraffins, 34.5% by volume of naphthenes and 3.5% by volume of aromatics.

In these Bamm comparison experiments conducted in one reaction with at least 200 ml of catalyst, lower temperatures, a higher pressure, a higher boiling gasoline and in particular a higher load than in Example 5. have been used. given in the following table: 20 U5408

Catalyst according to Nickel content, Time until DAS 1,180,481 weight percent first gasoline breakthrough 1 H | 15 from the beginning 2 H2 24.9 from the beginning 3 Hj 51.2 after 7 hours EXAMPLE · 7

Catalyst I:

Following the disclosures in German Patent Specification No. 1,227,603, a catalyst was prepared by precipitation. After filtering off the precipitate, a six times repeated hot slurry, alkalization and drying at 110 ° C, calcined at 450 ° C. Then the shredded mass was compressed while adding 2 # graphite to tablets of dimensions 5x5 mm. The analysis of the oxidic contact showed the composition (all percentages by weight) of 25.0 nickel, 65.4 Al 2 O 3, 3.05 potassium.

Catalyst K:

The catalyst was prepared analogously to Example 6 of German Patent Specification No. 1,227,603. The analysis of the oxidic contact showed the composition (all percentages by weight) 61.4 nickel, 19.5 AlgO ^, 1.31 potassium.

EXAMPLE 8

All of the catalysts H 1, I, K and A were tested for a comparison of their activity under the following conditions:

In each case, the experiments were conducted in the same reaction tube having an internal diameter of 24 mm and which was surrounded with an aluminum block. The inlet temperature of the mixture of naphtha and steam was 380 ° C. One of sulfurized naphtha with a density of 0.727 g / cm 2 and a boiling range between 80 and 21 was used. at a weight ratio of IO / hydrocarbon of 2.0 and a pressure of 30 atm. absolutely. The temperature of the surrounding aluminum block was 450 ° C.

As activity comparative size, the time was measured in hours after which the first amounts of higher hydrocarbons present in the fission gas did not occur. The results are shown in the drawing where, as ordinate, the time was chosen in hours (h) and where the catalysts are plotted on the abscissa.

Catalyst oxide, contact oxide contact Naphthaslip guard - # Nine weight # K or Na H1 15.2 0.01 from the beginning - h5 51.2 0.01 after 3 hours I 25.0 3.05 from the beginning K 61.4 1.31 after 89 hours A (Example 1) 56.8 0.009 after 121 hours